Understanding Interfacial Phenomena To Visualise And Unravel Fingerprints
thesisposted on 2019-07-09, 13:35 authored by Annelies Voorhaar
This research seeks to enhance the detection of fingerprints by two approaches; enhance currently used techniques using electrowetting and developing a novel detection method using molecularly imprinted polymers (MIPs). First, electrowetting was investigated as a method to enhance fingerprint visualisation. Aiming to make fingerprint molecules better accessible for fingerprint visualisation reagents and creating a more homogeneously distributed fingerprint ridge using a flow induced by electrowetting. The electrowetting process demonstrated to be able to induce flows in droplets, but for the formation of a flow in a fingerprint several challenges such as the physical and compositional structure of a fingerprint must still be overcome. Subsequently, to define the impact of a potential on a surface, potential-driven changes of surface characteristics were investigated. Conductive polymers were investigated as a surface, demonstrating that the hydrophobicity, composition and topography (roughness) could be tuned to a small or large extent. Second, MIPs were explored for the detection (visualisation and retrieving intelligence information) of fingerprints because of their chemical recognition characteristics and visualisation properties. By treatment of a fingerprint with fluorescent MIPs (targeted to albumin and trypsin) the fingerprint became fluorescent when the targeted molecules were present. Even tertiary level detail was observed which makes this technique promising for identification purposes. However, despite that the MIPs showed a higher affinity with their target molecule compared to other relevant molecules, it is questionable whether MIPs behave specifically under each circumstances. Possibly the accessibility and mobility of the MIPs in the fingerprint and substrate interactions affected the performance of the MIPs. This suggests that the affinity, size/shape and hydrophobicity of the MIPs as well as the viscosity, composition and physical structure of the fingerprint could be important for this application.